Weather, Climate, & Climate Models

Weather is the state of the atmosphere at a given time and place.

Weather is measured and described in a variety of ways by meteorologists, scientists who study and predict weather. Air temperature and air pressure, the amount and type of precipitation (hail, sleet, snow, rain, etc.) the strength and direction of wind, and the types of clouds in the sky (cirrus, stratus, cumulus, etc.)

Weather

Weather

Climate: The composite or generally prevailing weather conditions of a region averaged over a series of years.

Climate

Climate

Climates

According to NASA, “Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time.”

Weather is particular and fine-grained over short time scales.

Climate is general and broadly conceived over longer time scales.

Weather & Climate

Climate models simulate the Earth’s, a continent’s, or a region’s climate using fundamental understandings from the natural sciences to generate predictions of the climate’s behavior.

What is a climate model?

Physical laws (laws of motion, thermodynamics, etc.)

Topography & surface features Distribution of land and water* Atmospheric contents** Temperatures Insolation Albedo*** Size of the planet Gravity Speed of its rotation

Climate model attributes

Model must “predict” the behavior of the climate system. How?

Venus Jupiter Predict the past. Make predictions about future climate

behavior.

Climate models

How would you “predict” the past?

Climate models

What happens if you change the ice albedo effect?

What happens if you move Earth farther from the sun?

What happens if you change CO2?

What if you change H2O concentration?

Climate models